“Physically I’m doing great. It hasn’t been easy. I sacrificed so much to be at this event. I’m going to continue to get better. I had such a wonderful performance in my first grand slam back,” she added.

She was unable to say whether or not she would be fit for Wimbledon which gets underway in four weeks’ time.

“I’m beyond disappointed,” added three-time Roland Garros champion Williams who was playing in her first grand slam since winning the 2017 Australian Open.

It had been the most eagerly-awaited match of the tournament, coming just two days after Williams had blasted Sharapova’s autobiography for being “100 per cent hearsay” when it came to references about her.

Sharapova, the champion in Paris in 2012 and 2014, goes on to play a first quarter-final at the slams since losing to Williams at the same stage at the 2016 Australian Open.

It was in Melbourne that Sharapova tested positive for meldonium after which she served a 15-month doping ban. The Russian will face either 2016 champion Garbine Muguruza or Lesia Tsurenko of Ukraine for a semi-final place.